DIY 986 silencer replacement
DIY 986 silencer replacement
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Discussion

MogulBoy

Original Poster:

3,035 posts

241 months

Wednesday 16th July 2014
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I have an annoying rattle that I have been told is emanating from *within* the rear silencer box. It's certainly not the heat shields as they are rock solid (I had the bolts replaced a while ago). It's at its worst upon cold start but it also buzzes a low rpms when hot although it's barely noticable at road speed.

I'm tempted to fit a replacement OEM silencer but don't really fancy spending 10% of the value of the car on a new one so think I've found a used one for a 1/3rd of the new price and might have a go at fitting it myself...

Is this type of rattle getting more common as the cars age? I must say that I use mine daily and it up to temp virtually every journey so I don't think that I've been treating it badly....



I could get the back up on axle stands and have basic tools but I'm a bit nervous that it will be a tricky job best left to a mechanic on a ramp and all the tools. Any recent experience? I see that there are fitting kits available which presumably would be adviseable...


P.S. If I need to use my car to collect it, will it *almost* fit in the rear trunk (a Karcher almost fits!) or would it be a passenger seat job?


Edited by MogulBoy on Wednesday 16th July 16:43

ianwayne

7,169 posts

286 months

Wednesday 16th July 2014
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Are you sure it's not the twin exit pipes? It may not be the box itself.

I thought like you, that my rear silencer was rattling at low revs. It turned out to be the twin pipe trim bolted onto to the box. (it's a separate item on my car, I realise on some cars the twin pipes are welded on)

The captive nut on the back of the trim had a tack weld which had failed and the trim was a bit loose. It resonated at about 1200-1500 rpm. I've replaced it with stainless steel and bolt.

N.B. It's a b****d to get at. I had to use a disc cutter to get the old bolt off because the captive nut is inaccessible. It isn't now, I cut a bit of metal off the edge to give access to a 13mm spanner.

Edited to add: there's several whole boxes going on ebay at the moment. this one has no bids at 99p:

http://www.ebay.co.uk/itm/PORSCHE-BOXSTER-3-2-EXHA...


Edited by ianwayne on Wednesday 16th July 19:33

MogulBoy

Original Poster:

3,035 posts

241 months

Wednesday 16th July 2014
quotequote all
Up to 2002, (which mine is) the exhaust tips were part of the silencer but from 2003 onwards, it was a interchangeable part.

The part number on the one that I have found is 99611114202 (pictured). It was originally on an S but I believe that it is a direct replacement (only the tips are dual).

I guess that circa £200 for a used exhaust silencer with no provenance is a kind of Russian Roulette as it may also have issues. I might try to find out a bit more about the car it came off.

ianwayne

7,169 posts

286 months

Wednesday 16th July 2014
quotequote all
Done some more research. Yes, it seems the bolt on tip was only for 2003-04 for the 986 S model. No wonder there's so few on ebay!

edc

9,442 posts

269 months

Thursday 17th July 2014
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I've sold 2 used S exhausts, a prefacelift and facelift for about £60 each. You might consider sending your exhaust to Carnewal if you are going to take it off anyway.

MogulBoy

Original Poster:

3,035 posts

241 months

Monday 21st July 2014
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The answer to the question: Will a 986 silencer fit in the rear trunk...



...is yes. :-)

MogulBoy

Original Poster:

3,035 posts

241 months

Thursday 14th August 2014
quotequote all
Now done.

With the U-bends and hanger transferred over ready to re-fit the silencer.



A 6mm hex key required to transfer the flexible hanger/mount over. The two studs highlighted pass through an alloy mounting plate that is bolted to the back of the gearbox shown in the next image. When you are removing/refitting the silencer, you can undo all the other clamps/fastenings and the weight of the silencer will be supported by these studs at all times and it won't drop until you have undone the two nuts on these studs (a job that has to be done by feel with a 13mm socket, but there is enough room). Clearly you need to pull the silencer back to get these studs clear of the mounting plate hence the recommendation to remove the spoiler / rear bumper / impact bar first, but it would appear that there may be just enough room to manhandle it out with the bumper in-situ.



The holes that accept the two mounting studs.



There are 12 fasteners to undo in total to remove the silencer (not including the work to remove the spoiler and the rear PU etc.) and in theory, any one of them could cause you a headache but I didn't hit any major issues but i do live in a fairly dry climate here in the middle of Europe. I used new clamps and brackets supplied by an OPC and new plastic rivets to refit the spoiler as they were cheap as chips. The old clamps came off easily enough with liberal use of WD40 and a bit of persuasion from a hammer and chisel.

The second hand silencer sounds great and I was able to polish the visible bits quite easily with wet&dry paper / WD40 lube and then Autosol so I'm a happy bunny :-)